A few things first:
My game is installed to the xbox Hard Disk
I played up to my current point in 1 go (didn't turn off the xbox)

So I was replaying a mission for the "Complete XXX without getting hit". I got hit so I quit to the Hive, as I had done so many times before. The game then froze in the loading screen... now I purposefully install games to the hard drive when I see people saying achievements are glitching when they unlock, this prevents any kind of a disk read error from interfering, but to freeze in the loading screen?

So I took a break and came back, rebooted. I finished all the delivery and mechanic jobs, 100 wasp kills and finished the game. The badges unlocked but no achievements. I was frustrated and took a break again, but my brother saves my file to play another game. 300gs unlocked. In a nutshell, START -> SAVE GAME -> OVERWRITE. Achievements unlock

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Gotta love that this 98% of this forum only follows current games. No one remains active in forums of games they've finished. Good luck getting achievement tips for an original release.